Refrigeration compressor



1958 J. M. KEMPER 2,846,140

REFRIGERATION COMPRESSOR Original Filed June 9, 1947 2 Sheets-Sheet 1Zmventor JAMES M. KEMPER (Ittorneg Aug. 5, 1958 J. M. KE MPER ,1

REFRIGERATION COMPRESSOR Original Filed'June 9, 1947 2 SheetsSheet 2Zhwentor JAMES .M; KEMPER l (Ittbrneg States REFRIGERATION CDMPRESSORContinuation of application Serial No.

753,441, June 9, This application September 17, 1952, Serial No.

4 Claims. 01. 230-232 The present invention relates generally torefrigerating apparatus, and is more particularly concerned withmotorcompressor units for use in refrigerating apparatus of thecompression type, wherein the motor and compressor are enclosed within ahermetically sealed casing.

The present application constitutes a continuation of my copendingapplication Serial No. 753,441, filed June 9, 1947, now abandoned.

In units of the motor-compressor type as described herein, valve noiseshave in many cases proved objectionable and very difiicult to eliminate.Attempts have been made to utilize a muffier for suppressing oreliminating such noises, but these mufiiers have in the main been soconstructed that they could become filled with oil, whereupon anadditional slug of oil from the compressor might subject the mufiier toa sufficiently high pressure to cause bursting. As a further object, thepresent invention provides an improved muffier arrangement which is soconstructed that it will normally form a receiving chamber wherein aslight back pressure will be built up, and upon the occurrence of thispressure, relief means will be actuated to permit the discharge of fluidand draining of any accumulated oil.

Further objects of the invention will be brought out in the followingpart of the specification, wherein detailed description is for thepurpose of fully disclosing preferred embodiments of the inventionwithout placing limitations on the scope of the invention as defined inthe appended claims.

Referring to the drawings, which are for illustrative purposes only:

Fig. l is a side elevational view of a motor compressor unit embodyingthe features of the herein described invention;

Fig. 2 is an end elevational view looking toward the pumping end of theunit, a portion of the casing being cut away to disclose certain detailsof internal construction of the casing;

Fig. 3 is an enlarged vertical sectional view of the unit, takensubstantially on line 33 of Fig. 2;

'Fig. 4 is a fragmentary end view of the motor stator and rotor partsshowing certain constructional details thereof;

Fig. 5 is an exploded view showing the construction and inter-relationof the valve parts;

Fig. 6 is a sectional view through the suction head, taken on the line66 of the uppermost part of Fig. 5; and

Fig. 7 is an isometric view of the mufiler, a portion being cut away toshow details of construction.

Referring now to the drawings, it will be seen from Figs. 1, 2 and 3that the motor-compressor unit of the present invention is of verycompact construction of neat appearance, and comprises a sealed casingof two part construction, namely, a compressor part A and motor part B.The casing is generally l..-shaped in appearance with the compressorpart forming the vertical leg and the motor part of the horizontal leg.

hf i 2,846,140

Patented Aug. 5, 1958 The casing part A has a cylindrical opening 10 onone side which is peripherally surrounded by a groove 11 and aconnection flange surface 12. The casing part B is of hollowconstruction, generally cylindrical in shape and having one end closedand the opposite end open. The open end of the casing part B is providedwith a connection flange 13 adapted to abut and be secured against theflange surface 12 as by a plurality of securing screws 14. The inneredge portion of the connection flange 13 is provided with a groove 15for registration with the groove 11, these two grooves providing a spacefor receiving the peripheral edge portion of a bearing spider 16 whichis secured within the groove 11 as by a plurality of circumferentiallyspaced screws 17, the heads of these screws projecting into the groove15.

The bearing spider 16 has radially extending portions separated byopenings or open areas 18 therebetween to provide communication betweenthe opposite sides of the bearing spider. This bearing spider separatesthe interior of the casing into a compartment 19 for the pumpingelements as will be hereinafter described, and a compartment 20containing the motor for driving the pumping elements. The bearingspider is formed at its center with a tubular hub 21 for supporting ananti-friction bearing assembly 22 which is retained against movement inone direct-ion within the hub by a retainer ring 23 against which itabuts.

The bearing 22 forms a support intermediate the ends of a shaft 24 whichis rotatably mounted in this hearing with one end portion projectinginto the compartment 20 and its other end portion projecting into thecompartment 19. This latter end of the shaft 24 is supported by ananti-friction bearing assembly 25 supported within the annular wall of atubular bearing support 26 which in this case is integrally formed withthe adjacent wall portion of the casing part A. The anti-frictionhearing assembly 25 is composed of an inner ball race 25a which isclamped to the shaft end between a shaft shoulder 27 and a washer 28secured over the end of the shaft by a screw 29. A compression spring30, which is seated within the tubular bearing support, has one endbearing against a thrust washer 31, which engages against the outerbearing race 25b of the anti-friction bearing as sembly 25. With thisarrangement, the shaft is rotatably supported, and the spring 3t acts tobias the shaft axially in a direction toward the bearing spider 16 andmaintains a shaft shoulder 32 in continuous abutment with the inner ballrace 22a and the outer ball race 22b of the antifriction assembly 22continuously in abutting engagement with the retainer ring 23. Bymounting the shaft in this manner, close clearances are eliminated andthe shaft may readily respond to changes due to temperature variations.

The shaft section within the compartment 19 is provided with one or morecranks 33, depending upon and corresponding to the number of pumpingpistons in the compressor. The upper portion of the casing part A isformed with one or more cylinder bores 34 Within each of which there isreciprocably mounted a piston 35, each piston being connected by a wristpin 36 to the upper end of an associated connecting rod 37 having aconnection at its lowermost end with the crank 33.

Lubrication of the bearings and rotatable parts within the compartment19 is accomplished by means of oil scoop members 38 carried at thelowermost ends of the v connecting rod connection with the crank shaft,these oil scoops being adapted to dip into lubricating oil in the bottomof the casing, this oil being normally maintained substantially at theoil level as indicated by the numeral 39. It will be observed that theoil level is the same in both compartments 19 and 20, since free accessbetween 3 p the compartments is established through the openings or openareas 18 of the bearing spider.

The upper ends of the cylinder bores 34 terminate in a planar uppersurface which is capped by a hollow head member 41 seated on a sealinggasket 42 at its periphery on the surface 40 and secured in place by ap-lurality of head screws 43. The head member coacts with the surface 40to form a collecting chamber and valve compartment 44 within which thevalve assembly for each cylinder is mounted.

As shown in Fig. 2, adjacent and alongside the aligned cylinders, thecasing part A is cored or otherwise formed to provide an interior wallcavity 45 which communicates at its lowermost end with the interior ofthe compartment 19 and at its uppermost end with an inlet port 46 whichopens into the surface 41 a port 46 being provided for each cylindervalve assembly. With two cylinders, as illustrated in Fig. 3 of thedrawings, two inlet ports 46 would be provided.

Each valve assembly consists of a reed suction valve 47, a valve plate48, a reed discharge valve 49, and a suction head 50. These valveelements are assembled in stacked relation and secured by holding screws51. The reed valve members 47 and 49 are relatively held in properposition by small positioning pins 52 which are inserted into alignedopenings 53-,53' and 54-54 of these members.

The inter-relation of the valve elements to the cylinder bore is bestshown in the exploded view, Fig. 5. Fluid flow during suction stroke ofa piston will be as follows: From the inlet port 46, fluid will flowthrough registered openings 46a, 46b, and 460 in the valve elements 47,48, and 49 respectively. From the opening 460, the fluid flows into apassage or cavity 53a in the suction head 50, as shown in Fig. 6. Thepassage 53a interconnects opening 460 with the adjacently disposedopening 54b of the valve element 49. The opening 54b is in registrationwith an opening 54a through the valve plate 48. The underside of theopening 54a is closed by the end portion of a flexible tongue formed inthe reed suction valve member 47. The tongue 50 being disposed over thecylinder bore 34 will be drawn away from the lower end of the opening54a, during suction stroke of the piston, thus permitting fluid to passinto the cylinder.

During compression strokes of the piston, the compressed fluid is forcedthrough an opening 56 in the reed suction valve member 47, the opening56 being in registration with an opening 56a in the valve plate 48. Theuppermost end of the opening 56a is formed to provide a seat for the endportion of a flexible tongue 57 formed 0 in the reed discharge valvemember 49. The tongue 57 underlies a rib 58 which extends across adischarge opening passage 59'through the suction head 50, the lowermostedge of the rib 58 being upwardly curved as shown in Fig. 6, andindicated by the numeral 60 to permit limited upward flexing of thetongue 57 to open position in relation to the opening 56a.

Ordinarily, compressed fluid which is discharged through the dischargeopening 59 would pass directly into the valve compartment 44 and passout into the refrigerating system through an outlet conduit connection61. In the present invention, however, a hollow cover member isprovided, as shown in Fig. 7. This member is of relatively thin Walledsubstantially rectangular construction, and may be stamped or otherwiseformed from a flat metallic sheet so as to form a dished imperforatecover as generally indicated by the numeral 62. As shown in Fig. 3, thecover 62 is mounted in inverted .position with its brim forming edge 63seated on the surface 40 so as to cooperate therewith and enclose thevalve assemblies. One or more spring strips 64 riveted or otherwisesecured to the outermost surface of the upper wall portion of the coverhave curved end portions forming spring fingers 65 which are adapted to4 bear against the underside of the head member 41 to resiliently biasthe cover 62 downwardly into seated closed relation with the surface 40.

The cover 62 thus coacts with the surface 40 to form a fluid receivingchamber within the valve compartment for initially receiving the fluidas it is discharged from the valve assemblies. This cover serves as amuffler for suppressing the operating noises of the valves and willremain in closed position until a predetermined pressure, depending uponthe graduation of the springs 64, builds up within the receivingchamber. The spring fingers 65 may be so graduated as to permit a backpressure of four to five pounds per square inch to build up within thereceiving chamber, whereupon the cover 62 will be raised sufficiently topermit passage of fluid from the receiving chamber into the valvecompartment, and thence through the outlet connection 61. It will beobserved that any oil which might accumulate around the valve assemblywithin the receiving chamber under the cover 62 will be permitted todrain out of this chamher when the cover is raised and be carried intothe refrigerating system along with the refrigerant. The danger ofbursting the mufiler in such an arrangement is therefore entirelyeliminated.

The motor for actuating the pumping elements is contained Within thecasing part B and comprises a rotor element 66, which, in this case, isfor purposes of illustration disclosed as being of the squirrel cagetype, and a stator winding assembly 67.

The rotor element, which may be of conventional construction, isprovided with a central tubular hub 68 having an internal abutmentshoulder 69 which is engaged by the peripheral edge portion of aretaining washer 76 whichv is secured by a holding screw 71 to the endof the shaft 24. A spacer sleeve 72 surrounds the shaft end and ispositioned between the inner ball race 22a of the anti-friction bearing22 and the adjacent end of the hub 68 to limit and locate the rotor onthe. shaft.

The stator winding assembly comprises a plurality of stacked statorlaminations 73 mounted within a supporting ring member 74 which may havea pressed fit engagement on its outer surface with the interior of thecasing part B. The stator assembly includes the usual windings asgenerally indicated at 75, which it will be understood may constituteindividual coils assembledlin the grooves in the stator laminations 73in. accordance with usual practice. In addition to the winding grooves,the stator laminations' are provided with a plurality of passageways 76extending entirely through the stator laminations in an axial directionwith ends opening on opposite sides of the stator.

Stator winding connections are brought out througha plurality of leads77, each lead being connected with a sealed terminal connector whichincludes a bolt 78 supported within an opening 79 of the end wall of thecasing part B. The head of the bolt is insulated by insulating members80 from the adjacent casing part, and the shank portion of the bolt,where it passes through the wall of the casing, is insulated by atubular insulator 81. A clamp spacer member 82 of suitable insulatingmaterial surrounds the projecting threaded end of the bolt 78 and isheld in tight engagement with the adjacent casing material by means of asecuring nut 83 which is tightened against a washer 84 disposed betweenthe nut and spacer member.

It will be apparent from the foregoing description that by mounting thestator in the casing part B and by making this a unitary assembly whichmay readily be disconnected from the casing part A of themotor-compressor unit, it becomes a very easy matter to replace a burnedout or otherwise damaged rotor winding in the field with a replacementassembly, without the necessity of having to use special tools to get atand remove the damaged parts.

Above the electrical terminal connectors, the wall portion of the casingpart B is provided with an inlet 85 adapted for connection with aconduit for returning Tefrigerant and any oil particles or slugs of oilwhich may be contained therein back to the motor-compressor unit.

The returning refrigerant and any oil particles contained therein enterthe compartment 20 where contact is made with surfaces of moving andstationary parts of the motor assembly. In order for the refrigerant toreach the compartment 19, it is necessary for it to pass through themotor assembly, which it may do by flowing through the air gap betweenthe rotor and stator, and also by passage through the passageways 76 ofthe stator laminations. The oil particles in the refrigerating fluidwill be separated out and returned to the bottom of the easing and theoil and refrigerant will further act as a cooling medium for cooling themotor parts. The refrigerant then passes into the compartment 19 andfrom there may again be sucked into the cylinders and compressed, andstarted on another refrigerating cycle.

I claim as my invention:

1. In a fluid compressing unit having pumping elements therein: wallsforming a head chamber for collecting pumped fluid; valve means in saidchamber for controlling discharge of fluid from said pumping elements;an imperforate dished cover in said chamber positioned over said valvemeans with its edge seated on a wall of said chamber to oppose flow ofpumped fluid from said valve means into said head chamber; and springmeans acting against said cover normally biasing it in a seatingdirection, but enabling unseating in response to increased fluidpressure under said cover, so as to enable flow from said valve meansinto said collecting chamber.

2. In a fluid compressing unit having fluid cylinderpiston pumpingelements and a plurality of outlet valves: walls including a cylinderhead member defining a chamher for said valves and for collecting pumpedfluid; an imperforate dished cover in said collecting chamber over saidvalves with its brim adapted to seat on a wall surface in saidcollecting chamber and form a fluid receiving chamber for initiallyreceiving the fluid discharged from said pumping elements through saidvalve means; and means normally biasing the cover to seated position,but enabling raising movement upon increased pressure thereof.

3. The combination with a valve mechanism mounted in a cylinder headwall of a fluid compressing unit, of a dished imperforate coverpositioned over the valve mechanism to muflle its operating noises, saidcover having an offset brim edge forming a valve part adapted to seat onsaid wall; and spring means acting against the exterior of said covernormally biasing it in a direction to seat said brim edge on said wall,but enable unseating in response to increased fluid pressure under saidcover.

4. The combination in a fluid compressing unit, of a valve mechanismsupported in one Wallof a cylinder head valve compartment defined by aplurality of walls, a dished imperforate cover for the valve mechanismpositioned thereover, said cover having an offset brim edge adapted toform with said one wall, parts of a valve in series flow relation withsaid valve mechanism in a radial direction; and elongate strap springssecured in spaced relation on the exterior of said cover, the ends ofsaid springs being adapted to bear against another wall of said valvecompartment and bias the cover in a direction to seat its brim edge onsaid one wall.

References Cited in the file of this patent UNITED STATES PATENTS943,544 Hensley Dec. 14, 1909 947,431 De Grandsagne Jan. 25, 19101,628,096 \Vorth May 10, 1927 1,665,871 Wood Apr. 10, 1928 1,736,635Steenstrup Nov. 19, 1929 1,807,512 Culp May 26, 1931 1,889,122 HewittNov. 29, 1932 1,915,694 Reindel June 27, 1933 2,043,215 Smith et a1.June 2, 1936 2,140,328 Mozier Dec. 13, 1938 2,222,703 Bixler h Nov. 26,1940 2,235,962 Hormady Mar. 25, 1941 2,283,024 Wolfert May 12, 19422,327,810 McAverney Aug. 24, 1943 2,435,108 Touborg Jan. 27, 19482,452,807 Thompson Nov. 2, 1948 FOREIGN PATENTS 602,226 Germany Sept. 5,1934

